CONCEPT P4 INSTRUCTION MANUAL
5
4.
POWER CONTROL
Head Sensing
The CONCEPT P4 senses the presence of a head connected to it. In order to
turn a head on, the head must be connected to the unit. If the display of that
head does not turn on, the head on/off was left off last time that head was used:
just turn it on.
Note: the individual head double digit decimal display indicates whether the
head is on or off.
Decimal F-stops
The CONCEPT P4 power is displayed in DECIMAL f-stops. This system may
seem awkward at first, but it is actually quite simple.
f-stop
power
10
1/1
The individual displays
9.0
1/2
indicate the decimal
8.0
1/4
f-stop of each head.
7.0
1/8
6.0
1/16
Power Control on the CONCEPT P4
Each key click corresponds to ± 1/10 f-stop, which is observable on a flash
meter (± the precision of the flash meter). Don't think in Ws, nor power percent-
ages, but rather in increase or decrease of f-stop.
For example, you wish to increase by 1/2 (5/10) f-stop a power setting of 8.2:
just click the up key 5 times (to 8.7).
Power ratios between two heads are the difference between their displays. For
example, if Head A is at 8.0 and Head B is at 9.5, the power ratio is 1.5 (1 1/2) f-
stops, the difference between 9.5 and 8.0.
When using the Master Up or Down keys, notice that all displays increment or
decrement together, therefore preserving the light ratio between each head, as
the difference between the displays remains constant.
If any head reaches 10, the master up reaches its maximum.
If any head reaches 6.0, the master down reaches its minimum.
When power is lowered, you need to flash the unit (or the head) in order to
"dump" each head.
Power Control on the Head
PS-U/Z heads have their own power selector switch. It is used to increase or
decrease the power range of your CONCEPT P4. For accurate model lamp
AUTO ratioing, each head should be at the same nominal power.
Maximum power on each head is obtained with the selector in the 1 position.
Numbers in () give the f-stop decrease from 1,600 Ws.
1
1/2 or 2/3
1/4 or 1/3
PS-Z 4
1,600 Ws
1,066 Ws (-0.6)
533 Ws (-1.6)
PS-U 4
1,600 Ws
800 Ws (-1.0)
400 Ws (-2.0)
PS-U 3
800 Ws (-1.0)
400 Ws (- 2.0)
200 Ws (- 3.0)
A
Individual Head Control
Master Control
